tbuckley/cabot-search huggingface dataset:
IMMU-15. INTERPLAY BETWEEN <i>ATRX</i>AND <i>IDH1</i> MUTATIONS GOVERNS INNATE IMMUNE RESPONSES IN DIFFUSE GLIOMAS
Authors: Benjamin Whitfield, Seethalakshmi Hariharan, Christopher Pirozzi, Matthew Waitkus, Michael Brown, Michelle Bowie, David Irvin, Kristen Roso, Rebecca Fuller, Janell Hostettler, Sharvari Dharmaiah, Emiley Gibson, Aaron Briley, Avani Mangoli, Casey Fraley, Mariah Shobande, Kevin Stevenson, Gao Zhang, Prit Benny Malgulwar, Hannah Roberts, Martin Roskoski, Ivan Spasojevic, Steve Keir, Yiping He, Maria Castro, Jason Huse, David Ashley
Journal: Neuro-Oncology (2023)

Abstract Stimulating the innate immune system has been explored as a therapeutic option for the treatment of gliomas. Inactivating mutations in alpha-thalassemia retardation X-linked (ATRX) are defining molecular alterations in IDH-mutant astrocytomas and have been implicated in dysfunctional immune signaling. However, little is known about the interplay between ATRX loss and IDH mutation on innate immunity. To explore this interaction, we used both CRISPR and the RCAS/tva system to generate murine models of ATRX-deficient glioma, in the presence and absence of the IDH1 R132H mutation. We found that ATRX-deficient glioma cells were exquisitely sensitive to dsRNA-based innate immune agonism, displaying increases in inflammatory gene expression and profound cytokine release in vitro, while mice bearing ATRX KO tumors displayed increased T-cell infiltration and improved survival. The presence of IDH1 R132H dampened baseline expression of key innate immune genes and cytokines, with genetic and pharmacological inhibition of IDH1 R132H partially rescuing this suppression. Despite the suppression observed at baseline, IDH1 R132H expression did not interfere with the ATRX KO-mediated sensitivity to dsRNA agonism. These results demonstrate that ATRX loss primes cells for recognition of and activation against dsRNA, while IDH1 R132H reversibly masks this priming. Thus, this study suggests that innate immunity is a potential therapeutic vulnerability of astrocytoma. Further studies are in progress to validate the influence of ATRX loss on immune signaling and tumor-immune coevolution within human tumors.
PATH-35. SHIFTS IN GLIOMA PROGNOSTIC MOLECULAR FEATURES ACROSS THE LIFESPAN
Authors: Ruchit Patel, Hia Ghosh, E Antonio Chiocca, David Reardon, Patrick Wen, Sandro Santagata, Keith Ligon, Rameen Beroukhim, Wenya Linda Bi
Journal: Neuro-Oncology (2023)

Abstract INTRODUCTION Epidemiological studies examining glioma prognostic features have consistently identified older age as a negative predictor of survival. Accumulation and co-occurrence of favorable or deleterious molecular alterations across the lifespan likely plays a role in the age-dependent variability seen in glioma patient outcomes. METHODS We assembled 4,297 molecularly and clinically annotated glioma patients from multi-institutional datasets and TCGA, with IDH1/2-mutation, MGMT-methylation, and chromosome 1p19q codeletion status assayed. Patient age was stratified: pediatric (&amp;lt; 20 years), young adult (20-39 years), middle aged (40-64 years), and older adults ( &amp;gt;65 years). Pairwise proportions were tested to study distribution of alterations across age as well as variability in assaying for MGMT-methylation. RESULTS 4,297 patients with glioma were identified with molecular annotation of IDH1/2-mutation status (40.1% IDH1/2-mutant). Of assayed gliomas, 44.3% were MGMT-methylated and 13.9% had chromosome 1p19q codeletion. IDH1/2-mutation incidence decreased with age across all gliomas (85% in young adults, 35% middle aged, and 8% older adults) and in grade 4 gliomas (64% IDH1/2-mutation in young adults, 9% middle aged, and 2% older adults). 1p19q codeletion also decreased in incidence with increasing age (young adult 22%, middle aged 15%, older adults 6%). MGMT-methylation remained consistent across adult patients, between 43-50% across all gliomas. Interestingly, amongst the few patients &amp;gt;65 years old with IDH1/2-mutation or 1p19q codeletion, 87% possessed co-occurring MGMT-methylation, significantly greater than young adults (54%, p&amp;lt; 0.001). Consistent with this, 82% of patients &amp;gt;65yrs with grade 4 IDH1/2-mutant gliomas had co-occurring MGMT-methylation. Despite the treatment response implication of MGMT-methylation, 72.2% of low-grade gliomas were not assayed for MGMT. CONCLUSIONS There is an age-dependent pattern of molecular alterations in gliomas, with the incidence of certain favorable prognostic signatures decreasing over time. Given the stability of MGMT-methylation across the age spectrum and grade, more widespread MGMT profiling may be beneficial to guide treatment decisions.
EXTH-82. THE ROLE OF PTEN AND EPIGENETIC KINOME PROGRAMMING IN EGFR TKI RESPONSE IN GLIOBLASTOMA
Authors: Julia Ziebro, Abigail Shelton, Erin Smithberger, Benjamin Lin, Kasey Skinner, Allie Stamper, Ryan Bash, Frank Furnari, Christopher Miller
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma (GBM) is the most common brain tumor and standard therapy only extends survival from 12 to 15 months. The receptor tyrosine kinase EGFR is altered in ~60% of GBM, resulting in aberrant activation of downstream pathways, including PI3K, that potentiate tumorigenesis. Though EGFR targeting has been successful in other cancers, clinical trials with EGFR tyrosine kinase inhibitors (TKI) have failed in GBM, in part due to resistance. Trial results suggested that the most common oncogenic EGFR variant, EGFRvIII (vIII), and negative regulator of PI3K signaling, PTEN, were biomarkers of response. To dissect the role of PTEN in GBM tumorigenesis and EGFR TKI response, we utilized vIII-expressing mouse astrocytes with and without functional Pten. Pten loss potentiated tumorigenesis in vitro and in vivo, as proliferation and stemness were significantly increased, and mouse survival was decreased upon implantation as orthoptic allografts. Both RNA-seq and proteomic analysis using multiplex inhibitor beads with mass spectrometry (MIB-MS) showed significantly altered kinome profiles. Pten deleted cells were 5-fold more sensitive to the EGFR TKI neratinib, a drug that induced Pten-dependent modulation of the kinase transcriptome over 48h. This acute transcriptional adaptation implies alteration of the epigenetic landscape. We hypothesized that disruption of enhancer dynamics via BET bromodomain inhibition would improve EGFR TKI durability. We found that cells expressing Pten were 10-fold more sensitive to multiple BET inhibitors, including JQ1, birabresib, and molibresib, and these inhibitors synergized with neratinib to reduce proliferation only in the Pten wild type model. Ongoing work is focused on defining the role of PTEN in maintenance of differential transcriptional and epigenetic programs. We will explore potential mechanistic roles of both the enzymatic and non-enzymatic functions of Pten and characterize its effect on hallmark cancer phenotypes such as proliferation, stemness/self-renewal, and tumorigenesis in the presence and absence of EGFR ± BET inhibitors.
NIMG-33. [18F]-FLUOROMISONIDAZOLE RELATIVE PET INFLUX RATE IMPROVES DIAGNOSTIC ACCURACY FOR GLIOBLASTOMA PROGRESSION FROM THERAPY-INDUCED NEUROINFLAMMATORY PSEUDOPROGRESSION
Authors: Joseph Wishart, Ramon Barajas, Andrei Pugachev, Celeste Winters, Sadek Nemeh, Jana Ivanidze, Jeanne Link, Prakash Ambady
Journal: Neuro-Oncology (2023)

Abstract Glioblastoma is the most common and aggressive form of primary brain tumor in adults. Standard of care gadolinium-enhanced MRI (Gd-MRI) fails to capture hypoxia, a disease-defining feature of glioblastoma. Hypoxia potentiates resistance to chemo-radiation therapy (CRT) but is not extensively observed with therapy-induced pseudoprogression (PSP). This neuroinflammatory response to CRT occurs in approximately 40% of patients and is indistinguishable from disease progression by Gd-MRI, potentially causing unnecessary termination of effective therapy in patients with PSP. Additionally, delayed second line-therapy can occur in patients with resistance to CRT. This research evaluated whether [18F]-fluoromisonidazole (FMISO) positron emission tomography (PET), a noninvasive metric of tissue hypoxia, improves diagnostic accuracy in this context. Clinically, PET quantification employs the standardized uptake value (SUV), representing summed counts over an acquisition period. To add accuracy to this assessment, static 40-minute PET data acquired starting 90 minutes after FMISO injection was reconstructed into 20x2-minute frames and a relative Patlak model was applied. This technique forgoes blood sampling and extensive examination times required by traditional dynamic PET studies. The model produces two parameters that separately characterize the FMISO relative influx rate (Ki') and blood volume (VB'). In a cohort of 16 patients (3 IDH-mutated) imaged at a time of presumed disease progression, results showed that Ki' within the Gd-MRI enhancing lesion predicts future diagnosis of true progression (n = 11) or inflammation (n =5 ) with a sensitivity and specificity of 91% and 80% respectively. This outperforms diagnosis made with Gd-MRI alone, achieving ~70% for the same metrics. A t-test assuming unequal variance of cohort-wide mean Ki' tended toward significance (p = 0.07) for differentiating progressive disease (0.0036 ± 0.0016 min-1) from PSP (0.0011 ± 0.0017 min-1). RESULTS: from this study suggest relative Patlak analysis adds specificity to Gd-MRI and provides clinically relevant information regarding disease status.
QLTI-12. ADULT NEURO-ONCOLOGY TRIAL LANDSCAPE IN THE UNITED STATES OVER FIVE DECADES
Authors: Emily Smith, Anant Naik, Mahima Goel, Patrick Wen, Michael Lim, Susan Chang, Isabelle Germano
Journal: Neuro-Oncology (2023)

Abstract PURPOSE The unmet therapeutic needs in neuro-oncology remain significant due to the biological and clinical challenges. Clinical trials are important to close the gap between therapeutic unmet needs and scientific advances. This study aims at analyzing the landscape of neuro-oncology trials to identify completion and failures and guide strategies for the path forward. METHODS US-registered adult neuro-oncology clinical trials were extracted from www.clinicaltrials.gov (1966-2019) to include funding source, trial type, scope, phase, and subjects’ demographics. Trial failures comprised “terminated,” “withdrawn,” and/or “suspended” trials. Univariate and multivariate analysis were used to detect differences across factors and over time. RESULTS Our search yielded 4522 trials, 1257 eligible for this study. In 25 US States, neuro-oncology trials availability is &amp;lt; 0.85/100,000 population. Over time, completed trials have decreased with a significant increased percentage of trial failures from 22% to 36% (p &amp;lt; 0.001). Overtime, NIH funding decreased from 47% to 24% (p &amp;lt; 0.001). Inclusion of subjects ≥ 65-year-old and women increased in the last decade (p &amp;lt; 0.001) while inclusion of Hispanic subjects has decreased (p &amp;lt; 0.001). The top two reasons for failure included accrual and operational difficulties. Industry-funded trials had a trend toward higher failure rate than NIH-funded. A larger proportion of women (p &amp;lt; 0.001), non-Hispanic subjects (p = 0.001), and older adult (p &amp;lt; 0.001) patients were enrolled in completed trials than in failed trials. CONCLUSION Our study is the first report on the neuro-oncology clinical trial landscape in the US over time. The data support the concept that strategies to further the availability of clinical neuro-oncology trials within the US are necessary. As these are developed, attention is needed to identifying and modifying factors contributing to clinical trial failures.
EPID-28. YEARS OF LIFE LOST FOR BRAIN AND OTHER CENTRAL NERVOUS SYSTEM TUMORS IN THE UNITED STATES, 2018
Authors: Corey Neff, Mackenzie Price, Jakob Gerstl, Carol Kruchko, Jill Barnholtz-Sloan, Joshua Bernstock, Timothy Smith, Elizabeth Claus, Quinn Ostrom
Journal: Neuro-Oncology (2023)

Abstract Brain and other central nervous system tumors (BTs) contribute disproportionately to cancer morbidity and mortality relative to their incidence. To estimate the national burden due to these tumors in the United States (US), we estimated Years of Life Lost (YLL) due to premature death from BT overall and specific histopathologies. Mortality data for malignant and non-malignant BT were obtained from the National Vital Statistics System (~100% of US); survival data were obtained from the CDC’s National Program of Cancer Registries (NPCR, ~82% of the US) Survival Analytic Dataset for the years 2004-2018. YLL was calculated by adding estimated years of life left at their age of death. Mean YLL (mYLL) with corresponding 95% confidence intervals (95%CI) were reported by behavior, age at death, sex, and race/ethnicity for each data source, and by histopathology for NPCR. Total YLL due to malignant BT was 4,913,397 (mYLL=22.0) and 3,253,999 (mYLL=22.4), while non-malignant BTs contributed 208,278 YLL (mYLL=14.2). Females (mYLL=22.5), Hispanic individuals (mYLL=30.7), and children aged 0-14 years (mYLL=71.6), had the greatest mYLL due to malignant BTs. Glioblastoma had the highest total YLL (62.2% of all YLL, mYLL=19.8), while atypical teratoid/rhabdoid tumors had the greatest mYLL despite accounting for less than 1% of total YLL due to malignant BT (mYLL=74.4). Meningiomas accounted for 79% of total YLL due to non-malignant tumors, with a mYLL of 13.7. Compared to non-malignant BT, malignant BTs have the greatest mYLL, reflecting their short survival time post-diagnosis. BT are the most common type of cancer in children, leading to relatively high total (475,290 YLL) and mYLL for pediatric BT which may contribute substantially to cancer-specific mortality in this population. These estimates provide a compliment to other population-based BT statistics in demonstrating the impact of these debilitating tumors.
CTNI-48. SURVIVAL, TOXICITY, AND PATIENT REPORTED QOL OUTCOMES FOLLOWING PULSED REDUCED DOSE RATE RE-IRRADIATION WITH CONCURRENT BEVACIZUMAB FOR RECURRENT GRADE 4 GLIOMAS: RESULTS OF A PHASE II STUDY
Authors: Brett Morris, Adam Burr, Marissa Weiss, Nicholas Anger, Colin Harari, Wolfgang Tomé, Robert Bayliss, Ankush Bhatia, Patrick Grogan, Henry Robins, Steven Howard
Journal: Neuro-Oncology (2023)

Abstract Grade 4 gliomas are aggressive primary brain tumors with dismal prognosis despite maximal treatment. Recurrent disease is typically found within the prior radiation treatment field, complicating reirradiation. Pulsed reduced dose rate (PRDR) radiation is a treatment technique that reduces effective dose rate and increases treatment time allowing for intrafraction repair. Bevacizumab is a systemic VEGF inhibitor with efficacy in treating gliomas. We conducted a phase 2 prospective trial combining PRDR radiation with biweekly bevacizumab (10 mg/kg) in patients with recurrent grade 4 gliomas. Radiation was delivered with reduced dose rate delivered in 20 cGy pulses every 3 minutes in 2 Gy daily fractions to a total dose of 54 Gy. Kaplan Meier analysis was utilized to calculate progression free survival (PFS) and overall survival (OS). Toxicities were evaluated based on Common Terminology Criteria for Adverse Event v5.0 criteria. Mini Mental Status Examination (MMSE), as well as FACT-Brain, and FACIT-Fatigue patient reported quality of life (QoL) surveys were collected at baseline and follow up visits. Minimal important difference scores were calculated using by ½ standard deviation method. A total of 36 patients were enrolled, with 77% having previously received additional therapy for recurrent disease prior to study enrollment. Median PFS was 4.9 months and median OS was 6.9 months. No grade 4+ toxicity was observed. Two patients had grade 3 treatment related toxicity (seizure and radiation necrosis, both PRDR related). Treatment related grade 2 toxicity was seen in 44% of patients, primarily fatigue (30%). Clinically significant decrease in mean MMSE score, and FACT-BR QoL metrics across all sub-domains were noted in follow up. No clinically significant difference in mean FACIT-Fatigue QoL metric was observed. In this prospective phase 2 trial, PRDR with concurrent bevacizumab resulted in encouraging survival outcomes with acceptable toxicity in patients with recurrent grade 4 gliomas.
PATH-10. SURGICALLY RESECTED RECURRENT DIFFUSE GLIOMAS: HISTOMOLECULAR SPECTRUM
Authors: Ayushi Sahay, Manali Ranade, Archya Dasgupta, Aekta Shah, Abhishek Chatterji, Arpita Sahau, Amey Puranik, Indraja Dev, Aliasgar Moiyadi, Prakash Shetty, Vikas Singh, Nandini Menon, Tejpal Gupta, Sridhar Epari
Journal: Neuro-Oncology (2023)

Abstract Histological treatment-related changes (TRC) may mimic radiological progression in diffuse-gliomas on follow-up after complete therapy. If scans suggest recurrence, patients undergo re-surgery&amp; re-RT, if recurrence is histologically confirmed. We evaluated 1) baseline characteristics of surgically-resected gliomas re-operated for clinicoradiological suspected recurrence; 2) compared histological changes from initial surgery. All adult-type diffuse-gliomas (n=122) re-operated following complete therapy, with available initial&amp; subsequent slides reviewed, classified as per current WHO classification. Clinico-pathological features noted. RESULTS: Baseline median age:36years (IQR:29-44years), M:F=2.21, tumor-bed recurrence in majority (116/122). Of 92 astrocytomas, 47 were IDH-mutant (grade-2:18, grade-3:14, grade-4:15); 31 were IDH-WT (histological grade-2:4, grade-3:5, grade-4:22), IDH not-available (NA) in 14. Among IDH-mutant, 26 were MGMT-methylated (MGMT-M), 11 unmethylated (MGMT-UM). In IDH-WT 4 were MGMT-M, 23 MGMT-UM. Of 30 oligodendrogliomas, 21 were grade-2, 9 grade-3. All grade-2 gliomas (25astrocytoma, 21oligodendroglioma) showed high-grade transformation at re-surgery, with 40% astrocytoma upgrading to grade-3; 60% to grade-4. Six grade-3 astrocytoma recurred at same grade, while 18 as grade-4. Of 43 grade-4, on re-surgery 11 showed predominantly TRC ( &amp;gt;30%) with quiescent residual tumor (4 IDH-mutant, 5 IDH-WT, 2NA), while 32 showed recurrence (10 IDH-mutant, 18 IDH-WT, 4NA), of which 11 had scant (&amp;lt;5%) to focal (6-30%) TRC along-with actively proliferating tumor. Only 2 oligodendrogliomas showed TRC. Median disease-free interval (DFI) between both surgeries was significantly higher for oligodendroglioma (6.76years) than astrocytoma (3.59years, p-value&amp;lt; 0.001); for grade-2 (5.37years)&amp; grade-3 astrocytoma (5.19years) than grade-4 (2.85years, p-value&amp;lt; 0.001); grade-2 versus grade-3 oligodendroglioma (7.02years versus 4.91years, p-value 0.041), &amp;for MGMT-M versus MGMT-UM (5.17 versus 3.02years, p-value&amp;lt; 0.01). Significantly, median DFI was lower for grade-4 astrocytoma with TRC than without (2.34 versus 3.27years, p-value 0.015). CONCLUSIONS: Pseudo-progression gets confused with progression more commonly in high-grade gliomas than low-grade gliomas, and is associated with surgery closer to therapy completion. Careful histological assessment thus may help guide management.
CNSC-29. NKCC1 SIGNALING IN GLIOBLASTOMA REGULATES NEURONAL HYPEREXCITABILITY THROUGH GABAERGIC TONE
Authors: Saritha Krishna, Andy Daniel, Vardhaan Ambati, Clara Seibert, Shawn Hervey-Jumper
Journal: Neuro-Oncology (2023)

Abstract Over 90% of patients with glioma experience tumor-associated epilepsy, however first-line treatment fails to control seizures in most patients. Thus, there is a critical need to identify novel drivers of glioblastoma-induced neuronal hyperexcitability. We therefore used high-density electrode arrays to record local field potentials in vivo from gliomas. We then developed cerebral organoid and mouse models using primary glioblastoma cells from patients and neurons derived from induced pluripotent stem cells. Single-cell RNA sequencing (13,730 cells analyzed) in this system identified genes elevated in glioma-intrinsic neurons, including the sodium-potassium-chloride co-transporter 1 (NKCC1), which mediates chloride (Cl-) influx into cells. This elevated NKCC1 expression and subsequent increase of intracellular Cl- sets the reversal potential of GABAAR-mediated currents promoting depolarizing excitatory GABAergic responses. Electrophysiological analysis of glioma-neuron co-cultures using multi-electrode array and live-cell calcium imaging demonstrated increased network burst synchrony in the presence of NKCC1-high expressing tumor cells. Single-nucleus sequencing (54,000 cells analyzed) of embryonic neurons in co-culture with GBM cells further confirmed the elevated expression of circuit assembly genes including neuronal NKCC1. Live-cell imaging of iPSC-induced neuron organoids co-cultured with NKCC1-high-and low-GBM cells revealed increased migration and integration of NKCC1-elevated tumor cells. Mechanistic and functional studies validating therapeutic vulnerabilities to NKCC1 silencing by shRNA knockdown and by the FDA-approved diuretic drug, bumetanide was performed in vitro. The reduction in neuronal synchrony induced by NKCC1 downregulation correlated with a decrease in extracellular GABA and glutamate, suggesting a strong association between excitatory GABAergic and glutamate signaling with neuronal hypersynchrony in glioblastoma. Patient-derived xenograft in vivo experiments evaluated the effect of NKCC1 on tumor growth and progression and NKCC1-high GBM cells exhibited greater tumor burden compared to control mice. Collectively, these findings reveal a novel mechanism driving neuronal hyperactivity in glioblastoma and identifies potential therapeutic vulnerabilities for the treatment of glioma-associated epilepsy.
EXTH-65. IDENTIFICATION OF LOMERIZINE AS A POTENTIAL ANTI-GLIOBLASTOMA DRUG
Authors: Toshiya Ichinose, Shingo Tanaka, Masashi Kinoshita, Mitsutoshi Nakada
Journal: Neuro-Oncology (2023)

Abstract BACKGROUND Glioblastoma (GBM) is one of the most malignant primary brain tumors. Despite development of surgical techniques, chemotherapy and radiotherapy, GBM prognosis is still poor. Here, we identified lomerizine, a prophylactic drug for migraine, as a potential anti-GBM drug from thousands of existing compounds. We investigated its therapeutic effects both in vitro and in vivo with the purpose of drug repositioning. Materials and method: Human patient-derived glioma stem cell line (GSC; KGS01, KGS10, KGS15), their differentiated cells, and GBM cell lines (A172, SNB19, T98, U87) were used. Proliferation assay, migration assay and invasion assay were performed with all cell lines. Sphere-forming assay was performed with GSCs. Various signaling pathways altered by lomerizine were analyzed by Western blotting. In addition, induction of apoptosis was evaluated by immunofluorescence and Annexin V assay. Anti-GBM effects of lomerizine in vivo was validated with a mouse brain tumor model. Result: Lomerizine inhibited proliferation, migration, and invasion dose-dependently in all cell lines, especially in GSCs. Sphere formation was also suppressed by lomerizine in all GSCs. STAT3, which is involved in tumorigenesis, was dephosphorylated after the treatment with lomerizine in a dose-dependent manner in all cell lines. Furthermore, apoptosis induction by lomerizine was confirmed in both immunofluorescence and Annexin V assay. In vivo experiments showed a significant tumor suppression and prolongation of overall survival in the group of mice treated with lomerizine. CONCLUSION This study suggests that lomerizine has anti- GBM effects.